Conventional horizontal float switches for fluid level detection have a hinged plastic float that rotates up or down around a hinge or a spin nut depending upon a changing level of a fluid. Such conventional float switches include a magnet to actuate a reed switch in a pivoted motion of the float, the magnet being located typically towards the end of the float assembly or housing of the float switch. For proper rotation based operation of such conventional float switches, the magnet and the reed switch have to be precisely oriented during installation, which is a difficult goal to achieve. The rotational motion of the hinged plastic float that moves up or down makes it prone to breakage, wear and tear of hinge holes, and misalignment, for example, in heavy machinery operations where there are substantial vibrational forces involved. Due to such wear and tear of the hinges caused by rotating float, the pivot motion angle of the float is altered resulting in low error tolerance, incorrect readings and false alarms. Further, such conventional design of the float switch requires an extended housing to accommodate the wide sweep of rotation of the float, using more space and material, and also need to be oriented in appropriate position for proper function.
Some conventional fluid level detectors employ sensor based techniques. However, such sensor based design substantially increases costs and complexity of the design due to the electronics involved. Further, such conventional sensor based fluid level detectors are power hungry as they deploy active devices. The electronics of the sensor based fluid level detectors is also prone to malfunctioning in harsh environments, for example, in high vibration, temperature or pressure operations. This increases parts replacement and warranty related costs.
U.S. Pat. No. 4,056,979 ('979 patent), entitled “LIQUID LEVEL SENSOR,” is an example description of such a sensor based liquid level sensing device. The '979 patent purportedly is directed towards a liquid level sensor having a vertical guide tube with one or more magnetically operated switches therein at vertically spaced locations and a free float thereon which rises and falls with the liquid level and as it passes each switch magnetically latches it in one condition until the float returns in the opposite direction and unlatches it. The switches may be normally open, normally closed, or any combination, so that movement of the float past the switches may provide any desired circuit sequence.
However, the design discussed in the '979 patent is fixed in nature and needs the float to move over large distances with no options to realign the magnets of the float if they get misaligned. Accordingly, there is a need for an improved point level float switch.